1. Field of the Invention
The present invention relates to an LED package used for remote sensors, various lighting apparatuses and the like.
2. Description of Related Art
As a mode of an LED package, conventionally, a mode is widely known in which an LED element is disposed on a board that has a conductive part formed thereon, a case that encloses the LED element is arranged on the board, and a recess formed by the board and the case is filled with sealing resin. The internal surface of the case functions as a reflector that reflects light emitted from the LED element. The improvement in efficiency of extracting the light emitted from the LED element is intended by the case.
Meanwhile, in the LED package, when light is incident on the interface (opening face) between the sealing resin and the air, the absolute refractive index changes with the interface as the boundary, and thus if the incident angle of the light exceeds a critical angle defined by Snell's law, the light will be reflected by the interface. If such reflection is repeated, as the optical path becomes longer, the light is absorbed by the sealing resin, and there is a risk that the efficiency of extracting the light emitted from the LED element will conversely decrease.
In order to solve such a problem, for example, JP-A-2011-159951 discloses an LED package that is provided with a convex lens protruding in the light emission direction in order to focus the light emitted from the LED element and to increase the light extraction efficiency. Also, JP-A-2007-88075 discloses an LED package that can obtain the same effect as the LED package disclosed in JP-A-2011-159951 by shaping the sealing resin filled in the case to be convex so as to protrude in the light emission direction. However, both the LED packages disclosed in JP-A-2011-159951 and JP-A-2007-88075 have a convex projection formed therein, and thus there is a problem in that it is difficult to reduce the size and height of the LED packages.